The present invention relates to an attractant composition for Colorado potato beetles, which composition contains a carrier material and a Colorado potato beetle attracting effective amount of (a) (Z)-3-hexenyl acetate, (xc2x1)-linalool, nonanal, and methyl salicylate, (b) (Z)-3-hexenyl acetate, (xc2x1)-linalool, and methyl salicylate, (c) (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, and (xc2x1)-linalool, (d) (Z)-3-hexenyl acetate and methyl salicylate, or (e) (Z)-3-hexenyl acetate and (xc2x1)-linalool. The present invention also relates to a method for attracting Colorado potato beetles to an area of object or area, which method involves treating the object or area with a Colorado potato beetle attracting composition which contains a carrier material and a Colorado potato beetle attracting effective amount of (a) (Z)-3-hexenyl acetate, (xc2x1)-linalool, nonanal, and methyl salicylate, (b) (Z)-3-hexenyl acetate, (xc2x1)-linalool, and methyl salicylate, and wherein said beetles are larvae or adults, (c) (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, and (xc2x1)-linalool, (d) (Z)-3-hexenyl acetate and methyl salicylate, or (e) (Z)-3-hexenyl acetate and (xc2x1)-linalool.
In addition, the present invention also relates to a composition for repelling Colorado potato beetles, which composition contains a carrier material and a Colorado potato beetle repelling effective amount of (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, (xc2x1)-linalool, nonanal, methyl salicylate, and xcex2-caryophyllene. Furthermore, the present invention also relates to a method for repelling Colorado potato beetles from an object or area, which method involves treating the object or area with a Colorado potato beetle repelling composition which contains a carrier material and a Colorado potato beetle repelling effective amount of (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, (xc2x1)-linalool, nonanal, methyl salicylate, and xcex2-caryophyllene.
The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), is one of the most damaging insect pests of potatoes (Solanum tuberosum L.). Since it was first noted as a pest of potatoes in 1859, CPB has developed resistance to numerous chemicals that have been applied for its control (Casagrande, R. A., Bulletin of the Entomological Society of America, 142-150 (1987)). Alternatives to pesticides, e.g., biocontrol agents and host plant resistance, have had promising results and may enhance programs aimed at integrated pest management. Behavioral chemicals such as pheromones and plant attractants could also be useful both in survey and control of CPB (Dickens, J. C., Agricultural and Forest Entomology, 1: 47-54 (1999)).
Orientation of CPB to conspecifics and its host plant has been investigated intensively during this century. Although several studies have demonstrated the presence of a contact pheromone involved in CPB mating on the elytra of females (Jermy, T., et al., Entomologia Experimentalis et Applicata, 59: 75-78 (1991); Otto, D., Further evidence for the presence of a female sex pheromone in the Colorado potato beetle Leptinotarsa decemlineata Say. and its biological characterization, pp. 135-147, in H. Kleeberg and V. Micheletti (eds.), Practice Oriented Results on Use and Production of Neem Ingredients and Pheromones IV, Trifolio-M GmbH (1996)), proof of a sex pheromone that is active over a distance has been more elusive (DeWilde, J., et al., Netherlands Journal of Plant Pathology, 75: 53-57 (1969); Levinson, H. Z., et al., Naturwissenschaften, 66: 472-473 (1979); Edwards, M. A., et al., The Canadian Entomologist, 129: 667-672 (1997)). An olfactometer was devised that showed the attractiveness of volatiles emitted by potato plants to CPB adults (McIndoo, N. E., Journal of Economic Entomology, 19: 545-571 (1926)); the first demonstration that volatile emissions by plants attract insects. While various other investigators verified McIndoo""s initial observation (Schanz, M., Zeitschrift fxc3xcr vergleichende Physiologie, 35: 353-379 (1953); De Wilde, J., et al., Netherlands Journal of Plant Pathology, 75: 53-57 (1969); Visser, J. H., Entomologia Experimentalis et Applicata, 20: 275-288 (1976); Bolter, C. J., et al., Journal of Chemical Ecology, 23: 1003-1023 (1997)), specific chemical blends of plant odors responsible for attraction of CPB to potato plants have remained a mystery.
Volatiles emitted by intact potato plants, plants that were mechanically-damaged or plants that were damaged by insect feeding were identified in two separate studies (Bolter, C. J., et al., Journal of Chemical Ecology, 23: 1003-1023 (1997); Schxc3xctz, S., et al., Naturwissenschaften, 84: 212-217 (1997)). Bolter et al. (1997) revealed that feeding by CPB larvae on potato plants (cultivar Surprise) results in emission of a number of compounds including the green leaf volatile derivatives, (Z)-3-hexenol and (Z)-3-hexenyl butyrate, and the sesquiterpenes, xcex2-caryophyllene and xcex2-selenine. Linalool and indole were among volatiles emitted by CPB-damaged plants 24 hours following removal of the insects (Bolter et al., 1997). In their study, the blend of volatile compounds released by intact plants was not xe2x80x9cstrikingly differentxe2x80x9d from the blend emitted by insect damaged plants, and while a higher level of attraction of CPB was observed to insect- or mechanically-damaged plants, intact plants were also attractive. Schxc3xctz et al. (1997) used coupled gas chromatography/electroantennographic detector recordings to show that CPB antennae detect at least 18 compounds released by damaged potato plants (cultivar Granola). Benzene methanol and 2-benzene-ethanol were emitted by beetle-damaged plants but were not released by mechanically-damaged plants. Leaves sprayed with paraffin solutions of linalool, benzene methanol, 2-benzene-ethanol, or xcex2-caryophyllene were attractive to CPB, while xcex2-myrcene, nonanal and (Z)-3-nonen-1-ol applied in a similar manner reduced attraction.
Recently, there was disclosed a novel technique in which electroantennograms (EAGs) were recorded from CPB antennae that were challenged with equal amounts of compounds released by potato plants (an xe2x80x9cisosynthetic potato plantxe2x80x9d) delivered by gas chromatography (Dickens, J. C., Agricultural and Forest Entomology, 1: 47-54 (1999)). Employing serial dilutions to determine near threshold responses, these recordings showed that CPB, a generalist predator (Podisus maculiventris (Say) Hemiptera, Heteroptera: Pentatomidae), and a specialist predator (Perillus bioculatus (F.) Hemiptera, Heteroptera: Pentatomidae) of CPB possessed antennal olfactory receptors that were selectively sensitive to potato volatiles. Behavioral bioassays revealed that the generalist predator was attracted to a five-component volatile blend comprised of (E)-2-hexen-1-ol, (Z)-3-hexen-1-ol, nonanal, (xc2x1)-linalool, and methyl salicylate. CPB were attracted to a similar five-component blend in which the relative amounts of (E)-2-hexen-1-ol and (Z)-3-hexen-1-ol were decreased. This was the first synthetic attractant known for CPB. With the exception of (E)-2-hexen-1-ol for which CPB were more sensitive, antennal receptors of CPB were less sensitive to components of the blend than were both the generalist and specialist predators. Since green leaf volatiles (e.g., (E)-2-hexen-1-ol) are emitted at CPB feeding sites, it was hypothesized that such compounds might facilitate spacing of CPB on the plant, thereby improving its utilization by the insect.
In the present study, the behavior of CPB to natural and synthetic blends of volatiles emitted by potato plants was investigated.
In accordance with the present invention there is provided an attractant composition for Colorado potato beetles, which composition contains a carrier material and a Colorado potato beetle attracting effective amount of
(a) (Z)-3-hexenyl acetate, (xc2x1)-linalool, nonanal, and methyl salicylate,
(b) (Z)-3-hexenyl acetate, (xc2x1)-linalool, and methyl salicylate,
(c) (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, and (xc2x1)-linalool,
(d) (Z)-3-hexenyl acetate and methyl salicylate, or
(e) (Z)-3-hexenyl acetate and (xc2x1)-linalool.
Also in accordance with the present invention is a method for attracting Colorado potato beetles to an area of object or area, which method involves treating the object or area with a Colorado potato beetle attracting composition which contains a carrier material and a Colorado potato beetle attracting effective amount of
(a) (Z)-3-hexenyl acetate, (xc2x1)-linalool, nonanal, and methyl salicylate,
(b) (Z)-3-hexenyl acetate, (xc2x1)-linalool, and methyl salicylate, and wherein said beetles are larvae or adults,
(c) (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, and (xc2x1)-linalool,
(d) (Z)-3-hexenyl acetate and methyl salicylate, or
(e) (Z)-3-hexenyl acetate and (xc2x1)-linalool.
In addition, there is also provided a composition for repelling Colorado potato beetles, consisting essentially of a carrier material and a Colorado potato beetle repelling effective amount of (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, (xc2x1)-linalool, nonanal, methyl salicylate, and xcex2-caryophyllene.
Furthermore, there is also provided a method for repelling Colorado potato beetles from an object or area, comprising treating the object or area with a Colorado potato beetle repelling composition consisting essentially of a carrier material and a Colorado potato beetle repelling effective amount of (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, (xc2x1)-linalool, nonanal, methyl salicylate, and xcex2-caryophyllene.